and Magazine of the Ceylon A</ricultural Society. 



This appearance is precisely similar to that pre- 

 sented by other holes dug up by me upon former 

 occasions. I want to state Mr Petch's conditions 

 fairly as well as I understand thom, viz : — If 

 I had cut the same holes, mixed with the earth 

 taken out the same quantity, say, about 5 oz. 

 of basic slag and sulphate of potash and 

 refilled into the holes again, omitting 

 the prunings — will anyone contend for 

 one moment that these holes would now 

 present the same dark-coloured rich manurial- 

 looking appearance, full of rootlets?— in which 

 the rootlets of vegetation seem simply to luxu- 

 riate, fourteen months after this small 

 quantity of, say, oz. of basic slag and sul- 

 phate of potash per tea tree was applied, had 

 the prunings been omitted ? And as to 

 how the field is doing : In appearance 

 it is grandly healthy. It has just given 106 

 pounds of made tea per acre for this last short 

 month of February. But here I will be fair and 

 hasten to state that the field was manured 

 last October in alternate linos, viz., those in 

 which the prunings had not been buried and 

 the fine yield is no doubt largely due tu the 

 manure put in. The field has given to date 

 520lb. for 8 months with the best months to run, 

 our year ending 30th June, by which time I 

 expect it will have given 800 to 900 lb. tea. 

 The elevation of these estates would run from 

 about 3,500 up to near 5,000 and this particular 

 field would be, I should say, about 4,000 feet. 

 The field has been worked up from an average 

 yield of 430 lb. for seasons 1898-9, 1899-1900. 

 Although giving these additional particulars in 

 order to be quite fair, let us narrow the issue 

 down to — as Mr Petch pithily puts it— as to 

 whether " the same results would not have 

 been obtained if the prunings had been omitted." 

 My belief, or, say, my expectation, is that the 

 rich fertile appearance of the dug-up holes, full 

 of rootlets, would not be now apparent had only, 

 6ay, 5 oz. of basic slag and sulphate of 

 potash per hole to every four trees been 

 applied 14 months ago, all other conditions 

 being equal excepting only the omission oj 

 the prunings. Of course, it is admitted that 

 burying prunings would not suit every sod and 

 all conditions without exception. Commenting 

 on manuring vineyards with vine branches 

 another correspondent suggests the result 

 "Phylloxera," but as you practically say in 

 your comment he does not definitely connect 

 the effect he gives with the cause he assigns. 

 We know how very non-moral nature is : how 

 human cannibals have been found physically and 

 generally fitter than neighbouring non-cannibals, 

 and how much cannibalism there is throughout 

 nature; so that the objections to burying pru- 

 nings must be looked for uuUide that idea. I 

 myself can supply one great objection if labour 

 is short, viz., that the work is expensive in cooly 

 labour and this objection appeals very forcibly 

 to the man who has to get everything done and 

 wants to apply his labour elsewhere. In the 

 meantime my own attitude of mind is an open 

 one anxious to learn all I can upon the subject 

 of cultivation in its various branches. Thanking 

 Messrs. Petch, Fraser and others for their letters 

 on the subject,— I am, dear Sir, yours faithfully, 



JAS, M, B. DUNCAN. 



III. 



Mr. Petch Explains His Position. 



March 1st. 



Sik,— Mr. Cochran's figures support my state- 

 ment that tea prunings do not contain 4 per 

 cent of nitrogen. He analysed the prunings of 

 10 bushes, from Madulkele estate. They were 

 divided into two lots, — leaves, seeds and twigs 

 weighing (dry) 56 - 67 ounces, and twigs and 

 branches weighing (dry) 46"257 ounces. The 

 first gave 2794 per cent., and the second P26 per 

 cent, of nitrogen. The total dry weight was 

 102*927 ounces, containing 2-1 "per cent, of 

 nitrogen. Taking 3,110 bushes to the acre (Mr. 

 Cochran's estimate) the prunings remove 42 lb. 

 of nitrogen per acre, or, on a two-yearly pru- 

 ning, 21 lb. per annum. The total dry weight of 

 the prunings is 2,000 lb. per acre, or, assuming 

 as before that they lose 60 per cent, on drying, 

 5,000 lb. of green prunings per acre. If the 

 pruning is heavier, more wood is removed, and 

 the percentage of nitrogen is diminished. 



There is a misconception current with regard 

 to the relation of tea roots to the holes in which 

 prunings are buried. The direction and amount 

 of growth of roots is governed chiefly by the 

 water supply, and the roots " seek " the pru- 

 ning holes because the soil there is moister. The 

 material for the formation of these roots comes 

 from the bush. 



May I trespass further on your space to re- 

 state my position ? As the burying of prunings 

 of any cultivation, among the trees or bushes 

 from which they are taken, is a most extraordi- 

 nary proceeding from a mycological standpoint, 

 I raised the question in an article on Tea Root 

 Diseases in 19u6. It must have been discussed 

 without " prejudice," because it has since been 

 quoted in favour of both burying and burning ! 

 I was told that the whole questian had been 

 worked out long ago, and all details were known. 

 But I could not get at them, at least at anything 

 definite. Recently I have had occasion to in- 

 vestigate a new tea root disease, as far as time 

 permitted, and I took advantage of the first op- 

 portunity to re-open the subject. This time 

 we have been put in possession of the facts 

 relied on by the "other side"; and I have 

 ventured to criticise them. I think I have 

 shown that the amount of nitrogen in the 

 prunings is not the 4 per cent, claimed, and 

 that the experiments are not such as would 

 carry conviction at, say, Rothamstead, or 

 Woburn, or Wisley. 



Of course, the whole question is a matter 

 of balancing losses and gains : and te me the 

 gains appear to have been over-estimated. But 

 1 have no prejudice in the matter, beyond 

 a prejudice against unnecessary, i. c., avoid- 

 able, diseases. Root diseases of tea were first 

 brought to notice in 1901, and I have now 

 109 tea estates on the root disease list. That 

 is, 109 estates have sent in specimens for re- 

 port. Others have been seen when on tour, 

 and many estates do not bring their diseases 

 to Peradeniya. 



The advantages of burying prunings are : — 



(1) A gain in humus. 



(2) A certain amount of cultivation. 



(3) A gain in manures, 



